Some examples of connecting devices and cable connection systems include: U.S. Pat. Nos. 4,454,381; 7,552,803 B2; and 8,695,764 B2.
Currently, mainly cable screws are used for sealing and loading electrical devices installed in enclosures. Cable screws that correspond to International Electrotechnical Commission standard International Protection Marking IP69 are expensive and have the disadvantage that plastics such as cable coat shrink or crawl, thus leading to leaking over a period of time. In addition, cable screws can be improperly tightened, which can damage plastic and sealing parts, which also leads to malfunctions.
Systems with cable screws also have the serious disadvantage that a tightness or protective class up to IP 69 can be achieved by ring-shaped pressing of a rubber or elastomer ring, but also the jacket or sheath of a connection line is heavily constricted at the sealing point. Since the material of the jacket, often plastic PVC or PUR, ‘flows away’ with time due to the force of constricting, and leaks inevitably occur over time.
In the case of another system, a connecting part with which the connection cable is guided through the wall of the case part is equipped with a square assembly plate, which at each of the corners has a hole to accommodate a fastening screw to connect the connector part with the case part. In addition to drilling for the inclusion of a cylindrical base body in the connecting part, four additional threaded holes are required to attach this connection device to the case part, and four screws mounted into the connector device and the case part are required for assembly. This solution therefore requires a considerable amount of work and time.